JS——delete

<script>
    function fun(){

        this.name = 'mm';

    }

    var obj = new fun();

    console.log(obj.name);//mm

    delete obj.name;

    console.log(obj.name); //undefined
</script>

<script>
    var name = 'lily';
    delete name;
    console.log(name); //name is not defined
</script>

<script>
    function Person() {

    }
    Person.prototype.say='hello';
    var p=new Person();
    console.log(p.say);//hello
    delete p.say;
    console.log(p.say);//hello
</script>